Chilantaisaurus

Chilantaisaurus was a gigantic carnivore belonging to the Neovenatorid theropods. It was discovered in the Ulansuhai Formation in China and lived at the Late Cretaceous period. This colossus measured up to 13 meters (43 feet) in length, 4 meters (13 feet) tall at thr hip, and a mass of 6 tonnes. Though at first confused with Shaochilong due to superficial similarities, their size disparity soon cleared this mistake and while they both shared an ancestor to theropods like Allosaurus, carcharodontosaurids and neovenatorids are only very distantly related.

It likely fed upon very large herbivores, such as the therizinosaurid Nanshiungosaurus or even smaller predators such as the medium-sized carcharodontosaurid Shaochilong, which it would kill with its jaws and talons. Since its size and mass would only allow it to reach short bursts of high speed, it could have been an ambush predator or scavenger as well.

Its coloration and skin texture is unknown, but it could have been covered with scales and/or thin feathers and may have been brown, green or light blue in order to be able to cloak itself within the environment and effectively stalk unsuspecting prey as well as avoid unwanted attention from rivals.

Hu considered Chilantaisaurus to be a carnosaur related to Allosaurus,[6] though some subsequent studies suggested that it may be a spinosauroid, possibly a primitive member of the spinosaurid family (Sereno, 1998; Chure, 2000; Rauhut, 2001) because it had large claws on the forelimbs thought to be unique to that group. Other studies suggested that it could be a member of an alternate offshoot of neotetanuran theropods, with some similarities to allosauroids, spinosauroids, and coelurosaurians.[7] A 2009 study noted that it was difficult to rule out the possibility that Chilantaisaurus was the same animal as the carnosaur Shaochilong, which is from the same geological formation. However, they did note an enormous size difference between the two.[8] Further study by Benson, Carrano and Brusatte found that it was not as closely related to Shaochilong as first thought, but that it was a carnosaur (of the family Neovenatoridae), closely related to Allosaurus as Hu had initially thought.[1]

Several species have been described based on very poor remains. "Chilantaisaurus" sibiricus is based on a single distal metatarsal from the Turginskaya Svita of the Buryat Autonomous Soviet Socialist Republic, Russia, dating to the Early Cretaceous (Berriasian-Hauterivian).[9][10] It is poorly described, so its relationships cannot be accurately determined (Chure, 2000) and its placement as a species of Chilantaisaurus is highly questionable. "Chilantaisaurus" maortuensis was reclassified as Shaochilong maortuensis in 2009.[8] "Chilantaisaurus" zheziangensis, based on bones from the foot,[11] is actually a therizinosaur.

Chilantaisaurus is very obscure among the general public. However, it appeared in the Japanese book You Are Umasou and its anime adaptation (namely the second episode) where it tries to eat the titular baby Ankylosaurus (calling him "delicious") only to be ward off by the main Tyrannosaurus character. Chilantaisaurus also appears in the film adaptation of the book, but it is erroneously depicted with bull-shaped horns instead of stubby horns like other carnosaurs. This caused some viewers to think it was a Carnotaurus, despite it beared little resemblance to the abelisaurid.

Chilantaisaurus from the You Are Umasou animated shorts

Chilantaisaurus as it appears in You Are Umasou. Note the bull horns on its head